David Moyes has said he expects to be sacked if he fails to bring instant success to Manchester United.

Sir Alex Ferguson lasted 26 years at Old Trafford, but the Scot was afforded great patience during his early years as he struggled to turn the club around despite significant spending.

The decision to keep faith with the manager, given his ultimate success, demonstrates the potential value of continuity at a club, and the decision to offer Moyes a six-year contract illustrates United’s desire to maintain that approach.

Even so, Ferguson – appointed in 1986 – had to wait until 1990 to lift his first trophy with the Red Devils, and Moyes said he would “probably not” be afforded as much time as his predecessor.

“In this day and age, you would not get that,” Moyes, who failed to deliver silverware during his 11-year spell with Everton, told the Sunday newspapers. “I don’t think you can ever ask for time now. All you can ask for is to be judged on how it goes. Time is something managers do not get now and it is a tough start.”

Nonetheless, Moyes, who will have to take on Liverpool, Chelsea and Manchester City in his first five games, is confident his new employers will give him the freedom to carry out his duties as he sees fit.

“I have met the Glazers – Joel and Avi – both here and in New York and they have given me a lot of confidence to get on with the job,” he said. “Their message was to take your time and do things the way you want to do it. There are no great expectations on how I do the job. They are not owners who interfere.”

Moyes revealed his appointment had come entirely out of the blue.

“The phone rang and it was Sir Alex,” he said. “I had no idea why he would want to phone me. He said: ‘Could you drop over to the house for some lunch?’

“I told my wife that he must want me to take one of his players on loan or that he wanted to buy one of my players. I had my jeans and a T-shirt on and I felt I had to go home and get changed. I would never ever go to a meeting with Sir Alex wearing jeans.

“I had no inkling. He took me up the stairs, made me a cup of tea and spoke the words I will never forget. They were: ‘I am retiring and you are the next manager of Manchester United’. I went back to pick her up and Pamela must have wondered where the hell I had been. I told her: ‘I am the next Manchester United manager’. I cannot repeat what she said back.”

Moyes insists he is relishing the chance to follow on from the most successful manager of all time.

“I have heard so many people say that you don’t want to follow Sir Alex,” Moyes said. “A lot of good managers have said that you don’t want to take on that job, but he has left me a really good team and right now I feel fortunate.”